1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
|
//===-LTOCodeGenerator.cpp - LLVM Link Time Optimizer ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Link Time Optimization library. This library is
// intended to be used by linker to optimize code at link time.
//
//===----------------------------------------------------------------------===//
#include "LTOModule.h"
#include "LTOCodeGenerator.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Linker.h"
#include "llvm/Module.h"
#include "llvm/ModuleProvider.h"
#include "llvm/PassManager.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/CodeGen/FileWriters.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Mangler.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/StandardPasses.h"
#include "llvm/Support/SystemUtils.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/System/Signals.h"
#include "llvm/Target/SubtargetFeature.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetMachineRegistry.h"
#include "llvm/Target/TargetSelect.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Config/config.h"
#include <cstdlib>
#include <fstream>
#include <unistd.h>
#include <fcntl.h>
using namespace llvm;
static cl::opt<bool> DisableInline("disable-inlining",
cl::desc("Do not run the inliner pass"));
const char* LTOCodeGenerator::getVersionString()
{
#ifdef LLVM_VERSION_INFO
return PACKAGE_NAME " version " PACKAGE_VERSION ", " LLVM_VERSION_INFO;
#else
return PACKAGE_NAME " version " PACKAGE_VERSION;
#endif
}
LTOCodeGenerator::LTOCodeGenerator()
: _linker("LinkTimeOptimizer", "ld-temp.o"), _target(NULL),
_emitDwarfDebugInfo(false), _scopeRestrictionsDone(false),
_codeModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC),
_nativeObjectFile(NULL), _gccPath(NULL), _assemblerPath(NULL)
{
InitializeAllTargets();
InitializeAllAsmPrinters();
}
LTOCodeGenerator::~LTOCodeGenerator()
{
delete _target;
delete _nativeObjectFile;
}
bool LTOCodeGenerator::addModule(LTOModule* mod, std::string& errMsg)
{
return _linker.LinkInModule(mod->getLLVVMModule(), &errMsg);
}
bool LTOCodeGenerator::setDebugInfo(lto_debug_model debug, std::string& errMsg)
{
switch (debug) {
case LTO_DEBUG_MODEL_NONE:
_emitDwarfDebugInfo = false;
return false;
case LTO_DEBUG_MODEL_DWARF:
_emitDwarfDebugInfo = true;
return false;
}
errMsg = "unknown debug format";
return true;
}
bool LTOCodeGenerator::setCodePICModel(lto_codegen_model model,
std::string& errMsg)
{
switch (model) {
case LTO_CODEGEN_PIC_MODEL_STATIC:
case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
_codeModel = model;
return false;
}
errMsg = "unknown pic model";
return true;
}
void LTOCodeGenerator::setGccPath(const char* path)
{
if ( _gccPath )
delete _gccPath;
_gccPath = new sys::Path(path);
}
void LTOCodeGenerator::setAssemblerPath(const char* path)
{
if ( _assemblerPath )
delete _assemblerPath;
_assemblerPath = new sys::Path(path);
}
void LTOCodeGenerator::addMustPreserveSymbol(const char* sym)
{
_mustPreserveSymbols[sym] = 1;
}
bool LTOCodeGenerator::writeMergedModules(const char* path, std::string& errMsg)
{
if ( this->determineTarget(errMsg) )
return true;
// mark which symbols can not be internalized
this->applyScopeRestrictions();
// create output file
std::ofstream out(path, std::ios_base::out|std::ios::trunc|std::ios::binary);
if ( out.fail() ) {
errMsg = "could not open bitcode file for writing: ";
errMsg += path;
return true;
}
// write bitcode to it
WriteBitcodeToFile(_linker.getModule(), out);
if ( out.fail() ) {
errMsg = "could not write bitcode file: ";
errMsg += path;
return true;
}
return false;
}
const void* LTOCodeGenerator::compile(size_t* length, std::string& errMsg)
{
// make unique temp .s file to put generated assembly code
sys::Path uniqueAsmPath("lto-llvm.s");
if ( uniqueAsmPath.createTemporaryFileOnDisk(true, &errMsg) )
return NULL;
sys::RemoveFileOnSignal(uniqueAsmPath);
// generate assembly code
bool genResult = false;
{
raw_fd_ostream asmFile(uniqueAsmPath.c_str(), false, errMsg);
if (!errMsg.empty())
return NULL;
genResult = this->generateAssemblyCode(asmFile, errMsg);
}
if ( genResult ) {
if ( uniqueAsmPath.exists() )
uniqueAsmPath.eraseFromDisk();
return NULL;
}
// make unique temp .o file to put generated object file
sys::PathWithStatus uniqueObjPath("lto-llvm.o");
if ( uniqueObjPath.createTemporaryFileOnDisk(true, &errMsg) ) {
if ( uniqueAsmPath.exists() )
uniqueAsmPath.eraseFromDisk();
return NULL;
}
sys::RemoveFileOnSignal(uniqueObjPath);
// assemble the assembly code
const std::string& uniqueObjStr = uniqueObjPath.toString();
bool asmResult = this->assemble(uniqueAsmPath.toString(),
uniqueObjStr, errMsg);
if ( !asmResult ) {
// remove old buffer if compile() called twice
delete _nativeObjectFile;
// read .o file into memory buffer
_nativeObjectFile = MemoryBuffer::getFile(uniqueObjStr.c_str(),&errMsg);
}
// remove temp files
uniqueAsmPath.eraseFromDisk();
uniqueObjPath.eraseFromDisk();
// return buffer, unless error
if ( _nativeObjectFile == NULL )
return NULL;
*length = _nativeObjectFile->getBufferSize();
return _nativeObjectFile->getBufferStart();
}
bool LTOCodeGenerator::assemble(const std::string& asmPath,
const std::string& objPath, std::string& errMsg)
{
sys::Path tool;
bool needsCompilerOptions = true;
if ( _assemblerPath ) {
tool = *_assemblerPath;
needsCompilerOptions = false;
}
else if ( _gccPath ) {
tool = *_gccPath;
} else {
// find compiler driver
tool = sys::Program::FindProgramByName("gcc");
if ( tool.isEmpty() ) {
errMsg = "can't locate gcc";
return true;
}
}
// build argument list
std::vector<const char*> args;
std::string targetTriple = _linker.getModule()->getTargetTriple();
args.push_back(tool.c_str());
if ( targetTriple.find("darwin") != std::string::npos ) {
// darwin specific command line options
if (strncmp(targetTriple.c_str(), "i386-apple-", 11) == 0) {
args.push_back("-arch");
args.push_back("i386");
}
else if (strncmp(targetTriple.c_str(), "x86_64-apple-", 13) == 0) {
args.push_back("-arch");
args.push_back("x86_64");
}
else if (strncmp(targetTriple.c_str(), "powerpc-apple-", 14) == 0) {
args.push_back("-arch");
args.push_back("ppc");
}
else if (strncmp(targetTriple.c_str(), "powerpc64-apple-", 16) == 0) {
args.push_back("-arch");
args.push_back("ppc64");
}
else if (strncmp(targetTriple.c_str(), "arm-apple-", 10) == 0) {
args.push_back("-arch");
args.push_back("arm");
}
else if ((strncmp(targetTriple.c_str(), "armv4t-apple-", 13) == 0) ||
(strncmp(targetTriple.c_str(), "thumbv4t-apple-", 15) == 0)) {
args.push_back("-arch");
args.push_back("armv4t");
}
else if ((strncmp(targetTriple.c_str(), "armv5-apple-", 12) == 0) ||
(strncmp(targetTriple.c_str(), "armv5e-apple-", 13) == 0) ||
(strncmp(targetTriple.c_str(), "thumbv5-apple-", 14) == 0) ||
(strncmp(targetTriple.c_str(), "thumbv5e-apple-", 15) == 0)) {
args.push_back("-arch");
args.push_back("armv5");
}
else if ((strncmp(targetTriple.c_str(), "armv6-apple-", 12) == 0) ||
(strncmp(targetTriple.c_str(), "thumbv6-apple-", 14) == 0)) {
args.push_back("-arch");
args.push_back("armv6");
}
// add -static to assembler command line when code model requires
if ( (_assemblerPath != NULL) && (_codeModel == LTO_CODEGEN_PIC_MODEL_STATIC) )
args.push_back("-static");
}
if ( needsCompilerOptions ) {
args.push_back("-c");
args.push_back("-x");
args.push_back("assembler");
}
args.push_back("-o");
args.push_back(objPath.c_str());
args.push_back(asmPath.c_str());
args.push_back(0);
// invoke assembler
if ( sys::Program::ExecuteAndWait(tool, &args[0], 0, 0, 0, 0, &errMsg) ) {
errMsg = "error in assembly";
return true;
}
return false; // success
}
bool LTOCodeGenerator::determineTarget(std::string& errMsg)
{
if ( _target == NULL ) {
// create target machine from info for merged modules
Module* mergedModule = _linker.getModule();
const TargetMachineRegistry::entry* march =
TargetMachineRegistry::getClosestStaticTargetForModule(
*mergedModule, errMsg);
if ( march == NULL )
return true;
// The relocation model is actually a static member of TargetMachine
// and needs to be set before the TargetMachine is instantiated.
switch( _codeModel ) {
case LTO_CODEGEN_PIC_MODEL_STATIC:
TargetMachine::setRelocationModel(Reloc::Static);
break;
case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
TargetMachine::setRelocationModel(Reloc::PIC_);
break;
case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
TargetMachine::setRelocationModel(Reloc::DynamicNoPIC);
break;
}
// construct LTModule, hand over ownership of module and target
std::string FeatureStr =
getFeatureString(_linker.getModule()->getTargetTriple().c_str());
_target = march->CtorFn(*mergedModule, FeatureStr.c_str());
}
return false;
}
void LTOCodeGenerator::applyScopeRestrictions()
{
if ( !_scopeRestrictionsDone ) {
Module* mergedModule = _linker.getModule();
// Start off with a verification pass.
PassManager passes;
passes.add(createVerifierPass());
// mark which symbols can not be internalized
if ( !_mustPreserveSymbols.empty() ) {
Mangler mangler(*mergedModule,
_target->getTargetAsmInfo()->getGlobalPrefix());
std::vector<const char*> mustPreserveList;
for (Module::iterator f = mergedModule->begin(),
e = mergedModule->end(); f != e; ++f) {
if ( !f->isDeclaration()
&& _mustPreserveSymbols.count(mangler.getValueName(f)) )
mustPreserveList.push_back(::strdup(f->getName().c_str()));
}
for (Module::global_iterator v = mergedModule->global_begin(),
e = mergedModule->global_end(); v != e; ++v) {
if ( !v->isDeclaration()
&& _mustPreserveSymbols.count(mangler.getValueName(v)) )
mustPreserveList.push_back(::strdup(v->getName().c_str()));
}
passes.add(createInternalizePass(mustPreserveList));
}
// apply scope restrictions
passes.run(*mergedModule);
_scopeRestrictionsDone = true;
}
}
/// Optimize merged modules using various IPO passes
bool LTOCodeGenerator::generateAssemblyCode(raw_ostream& out,
std::string& errMsg)
{
if ( this->determineTarget(errMsg) )
return true;
// mark which symbols can not be internalized
this->applyScopeRestrictions();
Module* mergedModule = _linker.getModule();
// If target supports exception handling then enable it now.
if ( _target->getTargetAsmInfo()->doesSupportExceptionHandling() )
llvm::ExceptionHandling = true;
// if options were requested, set them
if ( !_codegenOptions.empty() )
cl::ParseCommandLineOptions(_codegenOptions.size(),
(char**)&_codegenOptions[0]);
// Instantiate the pass manager to organize the passes.
PassManager passes;
// Start off with a verification pass.
passes.add(createVerifierPass());
// Add an appropriate TargetData instance for this module...
passes.add(new TargetData(*_target->getTargetData()));
createStandardLTOPasses(&passes, /*Internalize=*/ false, !DisableInline,
/*VerifyEach=*/ false);
// Make sure everything is still good.
passes.add(createVerifierPass());
FunctionPassManager* codeGenPasses =
new FunctionPassManager(new ExistingModuleProvider(mergedModule));
codeGenPasses->add(new TargetData(*_target->getTargetData()));
MachineCodeEmitter* mce = NULL;
switch (_target->addPassesToEmitFile(*codeGenPasses, out,
TargetMachine::AssemblyFile,
CodeGenOpt::Aggressive)) {
case FileModel::MachOFile:
mce = AddMachOWriter(*codeGenPasses, out, *_target);
break;
case FileModel::ElfFile:
mce = AddELFWriter(*codeGenPasses, out, *_target);
break;
case FileModel::AsmFile:
break;
case FileModel::Error:
case FileModel::None:
errMsg = "target file type not supported";
return true;
}
if (_target->addPassesToEmitFileFinish(*codeGenPasses, mce,
CodeGenOpt::Aggressive)) {
errMsg = "target does not support generation of this file type";
return true;
}
// Run our queue of passes all at once now, efficiently.
passes.run(*mergedModule);
// Run the code generator, and write assembly file
codeGenPasses->doInitialization();
for (Module::iterator
it = mergedModule->begin(), e = mergedModule->end(); it != e; ++it)
if (!it->isDeclaration())
codeGenPasses->run(*it);
codeGenPasses->doFinalization();
return false; // success
}
/// Optimize merged modules using various IPO passes
void LTOCodeGenerator::setCodeGenDebugOptions(const char* options)
{
std::string ops(options);
for (std::string o = getToken(ops); !o.empty(); o = getToken(ops)) {
// ParseCommandLineOptions() expects argv[0] to be program name.
// Lazily add that.
if ( _codegenOptions.empty() )
_codegenOptions.push_back("libLTO");
_codegenOptions.push_back(strdup(o.c_str()));
}
}
|